Thread (9 messages) 9 messages, 2 authors, 2017-09-22

[PATCH 2/5] nvmem: mtk-efuse: use stack for nvmem_config instead of malloc'ing it

From: sean.wang@mediatek.com (Sean Wang)
Date: 2017-09-20 16:32:47
Also in: linux-mediatek, lkml

Hi, Masahiro

For maintainability, I felt it's better if we use the same way to
register nvmem as that most drivers does under nvmem usually using
static structure. Otherwise, they should also be changed to use the
one-time data in stack to avoid extra bytes to keep them.

	Sean


On Mon, 2017-09-11 at 22:01 +0900, Masahiro Yamada wrote:
quoted hunk ↗ jump to hunk
nvmem_register() copies all the members of nvmem_config to
nvmem_device.  So, nvmem_config is one-time use data during
probing.  There is no point to keep it until the driver detach.
Using stack should be no problem because nvmem_config is pretty
small.

Signed-off-by: Masahiro Yamada <redacted>
---

 drivers/nvmem/mtk-efuse.c | 24 ++++++++++--------------
 1 file changed, 10 insertions(+), 14 deletions(-)
diff --git a/drivers/nvmem/mtk-efuse.c b/drivers/nvmem/mtk-efuse.c
index 32fd572..fa7a0f6 100644
--- a/drivers/nvmem/mtk-efuse.c
+++ b/drivers/nvmem/mtk-efuse.c
@@ -49,7 +49,7 @@ static int mtk_efuse_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct resource *res;
 	struct nvmem_device *nvmem;
-	struct nvmem_config *econfig;
+	struct nvmem_config econfig = {};
 	void __iomem *base;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -57,19 +57,15 @@ static int mtk_efuse_probe(struct platform_device *pdev)
 	if (IS_ERR(base))
 		return PTR_ERR(base);
 
-	econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL);
-	if (!econfig)
-		return -ENOMEM;
-
-	econfig->stride = 4;
-	econfig->word_size = 4;
-	econfig->reg_read = mtk_reg_read;
-	econfig->reg_write = mtk_reg_write;
-	econfig->size = resource_size(res);
-	econfig->priv = base;
-	econfig->dev = dev;
-	econfig->owner = THIS_MODULE;
-	nvmem = nvmem_register(econfig);
+	econfig.stride = 4;
+	econfig.word_size = 4;
+	econfig.reg_read = mtk_reg_read;
+	econfig.reg_write = mtk_reg_write;
+	econfig.size = resource_size(res);
+	econfig.priv = base;
+	econfig.dev = dev;
+	econfig.owner = THIS_MODULE;
+	nvmem = nvmem_register(&econfig);
 	if (IS_ERR(nvmem))
 		return PTR_ERR(nvmem);
 
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